In systems of this type, the individual panels are placed over the substrate and clipped to it. The panels are then joined by seams along their adjacent edges. The seams are covered by battens.
In some systems, the batten clips over adjoining edges of panels and forms a separate element. See for example, Andrews, U.S. Pat. No. 4,400,924.
In improved systems, the batten is made an integral part of the panel to save construction time. See, for example, the METALINE.TM. roof system of Astraline Corporation, Teterboro, N.J. In this later type of system, the panel has two distinct longitudinal edges, a longitudinal edge being defined as an edge running along the length of the panel.
One longitudinal edge is bent to form the aforementioned batten. The opposite longitudinal edge is bent to form a lockseam.
A lockseam is a bend curving back on but not actually touching the panel. The resulting gap which lies between the bend and the panel is intended to receive a corresponding lock lip, which protrudes from the end of the batten of an adjacent panel.
In the METALINE.TM. system, there is also a water dam behind the lock gap in the lockseam. Each panel in the METALINE.TM. system is secured to the substrate by clips which hook over the top of the water dam.
In some environments, strong wind uplift and shear forces may act on the panels. These forces are transferred both to the lockseams holding the panels together and the clips holding the panels to the substrate. The combination of the vertical uplift and horizontal wind shear forces may eventually cause the panels to twist out of the holding clips. The lockseams may also deform in the area of the lock gaps permitting the lock lips of adjacent panels to pop out.
Hence, in environments where strong wind uplift and shear forces may be encountered regularly, an improved lockseam and clip arrangement is needed.
It is also desirable to provide a lockseam with a receiving space suitable for receiving a bead of caulking compound and into which the lock lip may penetrate after insertion thereof through the lock gap. This bead of caulking compound is beneficial because it provides an added measure of protection against water infiltration through the lockseam. The caulking also acts as an adhesive to help hold the lock lip in place.
In addition, in some roofing situations, people may need to walk on the roof, to service roof mounted equipment. When roof panels are made out of soft metals like zinc and copper, additional support may be needed under the battens to prevent deformation. However, the support must not dramatically increase construction time.